Input device and method of detecting an input

ABSTRACT

An input device is described which comprises a touch-sensitive surface and a force sensor, wherein the force sensor is adapted to detect a force applied to the touch-sensitive surface. The input device further comprises a vibration sensor and a control unit, wherein the control unit is coupled with the force sensor, the touch-sensitive surface and the vibration sensor. The control unit is adapted to validate a force detected by the force sensor as an input in dependence on a touch of the touch-sensitive surface and in dependence on a vibration detected by the vibration sensor. There is further described a motor vehicle which comprises such an input device. A method of detecting an input at an input device is further described.

TECHNICAL FIELD

The present disclosure relates generally to the field of input devicesfor executing user inputs. Specifically, there is proposed an inputdevice which comprises a vibration sensor for validating inputs. Acorresponding validation method is further provided.

BACKGROUND

Input devices are used in many technical systems, such as, for example,in screens, mobile telephones, motor vehicles and tablet computers, etc.

Touch-sensitive surfaces are increasingly being used in input devices.Such surfaces are to be operated intuitively and, in combination with adisplay unit, can give a user optical feedback when touched. An inputdevice can further comprise a force sensor which detects the applicationof a force to the touch-sensitive surface. For example, a user can movea mouse pointer onto a switch symbol by means of the touch-sensitivesurface and trigger operation of the switch symbol by applying anincreased force to the touch-sensitive surface.

Input devices of the above-mentioned type are also used inter alia inmobile or machine-oriented areas in which they are exposed tovibrations. Such areas include, for example, mobile telephones, sportselectronics, vehicles or industrial machines. Any vibrations which occurhere can lead to unintentional operation of the input device. The reasonfor this is, for example, acceleration of the input device or of a userdue to acceleration, so that the user unintentionally touches thetouch-sensitive surface or exerts increased force thereon. The inputdevice can misinterpret this as inputs.

Erroneous inputs can lead to loss of time, miscommunication andaccidents. When operating motor vehicles and other machines inparticular, corresponding safety considerations play a major role.

Publication US 2009/0243817 A1 discloses an input device which is ableto detect touches and force applications by means of a matrix ofcapacitive sensors. The input device is equipped with an accelerationsensor in order to disregard force applications when vibrations aredetected by the acceleration sensor. However, because both the forceapplication and the touch are detected by the same sensor system, theinput device is not able to distinguish reliably between auser-generated vibration and an external vibration. An excessivelyforceful input by a user could be misinterpreted as external vibrationand wrongly discarded.

SUMMARY

The object underlying the present disclosure is to provide an inputdevice which permits improved validation of an input.

According to a first aspect there is provided an input device whichcomprises a touch-sensitive surface, a vibration sensor and a forcesensor, wherein the force sensor is adapted to detect a force applied onthe touch-sensitive surface. The input device further comprises acontrol unit which is coupled with the force sensor, the touch-sensitivesurface and the vibration sensor, wherein the control unit is adapted tovalidate a force detected by the force sensor as an input in dependenceon a touch of the touch-sensitive surface and in dependence on avibration detected by the vibration sensor.

The touch-sensitive surface can detect a touch, for example, optically,acoustically, resistively or capacitively. The touch-sensitive surfacecan output the touch to the control unit in the form of a touch signal.The control unit can detect a touch as an indication of an input onlyafter a minimum area is touched. The minimum area can be chosendepending on signals of the force and/or vibration sensors.

The force sensor can measure a force application, for example, on thebasis of an elastic deformation, a distance change or by means ofpiezoceramic elements or resistive sensors. The force sensor can outputthe force application to the control unit in the form of a force signal.The control unit can detect an applied force as an indication of aninput when the applied force exceeds a force threshold. The forcethreshold can be chosen depending on signals of the touch-sensitivesurface and/or of the vibration sensor. The force sensor can be adaptedto detect a force application substantially perpendicular to thetouch-sensitive surface. The control unit can be adapted to detect,process or store (e.g. by activating and/or reading the force sensor) aforce signal only after a time of a detected touch of thetouch-sensitive surface.

The vibration sensor can comprise an acceleration sensor. The vibrationsensor can output the vibration to the control unit in the form of avibration signal. The control unit can detect a vibration as such whenit exceeds a vibration threshold value. The vibration threshold valuecan be chosen depending on signals of the touch-sensitive surface and/orof the force sensor. The vibration sensor can be adapted to detect adirection of the vibration. The control unit can be adapted to detect,process or store (e.g. by activating and/or reading the vibrationsensor) a vibration signal only after a time of a detected touch.

The vibration sensor can be arranged on the touch-sensitive surface, ona casing of the input device, or on an element that is rigidly connectedto the casing. The vibration sensor can detect a vibration in adirection substantially perpendicular to the touch-sensitive surface.Alternatively, the vibration sensor can detect a vibration in anyspatial direction.

The control unit can be adapted to evaluate a force detected by theforce sensor as an input in the case where there is a simultaneous atouch of the touch-sensitive surface and where a vibration thatcorrelates temporally with the force detection is absent. In addition oralternatively, the control unit can be adapted to discard a forcedetected by the force sensor as an input in the case where there is asimultaneous touch of the touch-sensitive surface and where there is avibration that correlates temporally with the force detection.

The control unit can be adapted to evaluate a temporary interruption ofa force detected by the force sensor as an indication of a terminationor interruption of the input (and optionally as a new input) in theabsence of a vibration that correlates temporally with the interruption.The control unit can be adapted to discard a temporary interruption of aforce detected by the force sensor as an indication of a termination orinterruption of the input in the case where there is a vibration thatcorrelates temporally with the interruption.

The control unit can be adapted to determine from the detected vibrationand the detected force a component of the detected force that isintended by a user and to evaluate the intended force component as aninput.

The control unit can be adapted to determine from the detected vibrationand the detected force a component of the detected force that isintended by a user and to discard the detected force as an input whenthe force component of the detected force that is intended by a user isundeterminable. Validation according to claim 1 can include evaluationas an input and/or discarding as an input in this sense.

The control unit can be adapted to determine the intended component ofthe detected force by reducing the detected force by avibration-dependent value. The control unit can be adapted to includetime derivatives and/or integrals of the detected force and/or of thevibration when determining the intended component of the detected force.

The control unit can be adapted to take into account in the validationdurations of the force application and of the vibration. In addition oralternatively, the control unit can be adapted to take into account inthe validation a temporal sequence of the detection of the forceapplication and of the vibration. The control unit can specify a timecriterion for a temporal correlation between a vibration and a forceapplication. The time criterion can include a time threshold value for atime difference between durations of the force application and of thevibration. The time criterion can include a maximum and/or minimum valuefor a ratio between the durations of the force application and of thevibration. The control unit can have a temporal sequence criterion for acorrelation between a vibration and a force application. The sequencecriterion can include a maximum time offset between detection of thevibration and of the force application. The sequence criterion caninclude detection of the vibration temporally before detection of theforce application.

According to a second aspect there is provided an input device whichcomprises a touch-sensitive surface. The input device further comprisesa vibration sensor and a proximity sensor, wherein the proximity sensoris adapted to detect an approach of an input element to thetouch-sensitive surface. The input device further comprises a controlunit which is coupled with the touch-sensitive surface, the proximitysensor and the vibration sensor, wherein the control unit is adapted tovalidate a touch detected by the touch-sensitive surface as an input independence on an approach detected by the proximity sensor and avibration detected by the vibration sensor.

The proximity sensor can detect an approach, for example, inductively,capacitively, magnetically or optically. The control unit can evaluatean approach as such when a distance between the touch-sensitive surfaceand an input element falls below a threshold value. The control unit canbe adapted to detect, process or store (e.g. by activating and/orreading the touch-sensitive surface) a touch signal only after a time ofa detected approach.

The control unit can be adapted to evaluate a touch detected by thetouch-sensitive surface as an input in the case where an approach issimultaneously detected by the proximity sensor and where a vibrationthat correlates temporally with the detected touch is absent. Inaddition or alternatively, the control unit can be adapted to discard atouch detected by the touch-sensitive surface as an input in the casewhere an approach is simultaneously detected by the proximity sensor andwhere there is a vibration that correlates temporally with the touchdetection.

The control unit can be adapted to evaluate a temporary interruption ofa touch detected by the touch-sensitive surface as an indication of atermination or interruption of the input (and optionally as a new input)in the absence of a vibration that correlates temporally with theinterruption. The control unit can be adapted to discard a temporaryinterruption of a touch detected by the touch-sensitive surface as anindication of a termination or interruption of the input in the casewhere there is a vibration that correlates temporally with theinterruption.

The control unit can be adapted to take into account in the validationdurations of the touch and of the vibration. In addition oralternatively, the control unit can be adapted to take into account inthe validation a temporal sequence of the detection of the touch and ofthe vibration. The control unit can specify a time criterion for atemporal correlation between a vibration and a touch. The time criterioncan include a time threshold value for a time difference betweendurations of the touch and of the vibration. The time criterion caninclude a maximum and/or minimum value for a ratio between the durationsof the touch and of the vibration. The control unit can have a temporalsequence criterion for a correlation between the vibration and thetouch. The sequence criterion can include a maximum time offset betweendetection of the touch and of the vibration. The sequence criterion caninclude detection of the vibration temporally before detection of thetouch.

The input device can further comprise a display unit. Thetouch-sensitive surface can be adapted to detect a touch in the regionof the display unit. The display unit can be based, for example, onliquid crystal, plasma, light-emitting diode or organic light-emittingdiode technology. The display unit can be arranged spaced apart from thetouch-sensitive surface. Alternatively, the display unit can be formedwith the touch-sensitive surface as a single unit.

According to a third aspect there is provided a motor vehicle, whereinthe motor vehicle comprises the input device proposed herein. The inputdevice can control, for example, a radio, an on-board computer, anavigation system or an infotainment system of the motor vehicle.

According to fourth aspect there is provided a method of detecting aninput at an input device. The input device has a touch-sensitivesurface, a vibration sensor and a force sensor, wherein the force sensoris adapted to detect a force applied to the touch-sensitive surface. Themethod comprises validating a force detected by the force sensor as aninput in dependence on a touch of the touch-sensitive surface and independence on a vibration detected by the vibration sensor.

A force detected by the force sensor can be evaluated as an input in thecase where there is a simultaneous touch of the touch-sensitive surfaceand where a vibration that correlates temporally with the forcedetection is absent.

According to a fifth aspect there is provided a method of detecting aninput at an input device. The input device has a touch-sensitivesurface, a vibration sensor and a proximity sensor, wherein theproximity sensor is adapted to detect an approach of an input element tothe touch-sensitive surface. The method comprises validating a touchdetected by the touch-sensitive surface as an input in dependence on anapproach detected by the proximity sensor and a vibration detected bythe vibration sensor.

A touch detected by the touch-sensitive surface can be evaluated as aninput in the case where an approach is simultaneously detected by theproximity sensor and where a vibration that correlates temporally withthe touch detection is absent.

According to a sixth aspect there is provided a computer program productwhich is stored on a computer-readable medium, wherein the computerprogram product comprises instructions which, when carried out on aprocessor, cause a method as presented herein to be performed.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, details and features of the present disclosure willbecome apparent from the following description of exemplary embodimentsand from the figures, in which:

FIG. 1 is a sectional view of a first exemplary embodiment of an inputdevice;

FIG. 2a is a sectional view of the first exemplary embodiment during anoperation without external vibration;

FIG. 2b is a sectional view of the first exemplary embodiment withoutoperation and with external vibration;

FIG. 2c is a sectional view of the first exemplary embodiment during anoperation and with external vibration;

FIG. 3 is schematic diagrams of sensor signals of the sensors from FIGS.2a -2 c;

FIG. 4 is schematic diagrams of sensor signals with a time offsetbetween the detected force and the detected vibration;

FIG. 5 is schematic diagrams of sensor signals during an interruption ofa detected force due to a vibration with a time offset between thedetected force and the detected vibration;

FIG. 6 is a flow diagram of a first exemplary embodiment of a method ofdetecting an input;

FIG. 7 is a flow diagram of a second exemplary embodiment of a method ofdetecting an input;

FIG. 8 is a sectional view of a second exemplary embodiment of an inputdevice; and

FIG. 9 is a flow diagram of a third exemplary embodiment of a method ofdetecting an input.

DETAILED DESCRIPTION

FIG. 1 shows a sectional view of a first exemplary embodiment of aninput device 10. The input device 10 can be installed in a fixed mannerin a motor vehicle or in a mobile device, for example a tablet computeror a smart phone.

The input device 10 comprises a functional unit 12 having atouch-sensitive surface 14, wherein the touch-sensitive surface 14 isarranged on a side of the functional unit 12 facing the user. On a sideof the functional unit 12 facing away from the touch-sensitive surface14 there is provided, spaced apart therefrom, a display unit 16. Thetouch-sensitive surface 14 is permeable to light, so that the displayunit 16 is visible to a user through the touch-sensitive surface. Thesides of the functional unit 12 and of the display unit 16 that face oneanother extend substantially parallel to one another.

In an alternative form, the display unit is formed with thetouch-sensitive surface 14 as a single unit. This single unit thus formsat least part of the functional unit 12 according to FIG. 1. In thiscase, the counter-element required for the functional unit 12 for forcedetection is not the display unit 16 according to FIG. 1 but anotherrigid element, such as, for example, a printed circuit board or part ofa casing.

Between the functional unit 12 and the display unit 16 there areprovided elastic elements 18 which are mechanically connected to thefunctional unit 12 and to the display unit 16. When a force is appliedto the touch-sensitive surface 14 in a direction substantiallyperpendicular to the touch-sensitive surface 14, the elastic elements 18are deformed, with the result that the distance between the functionalunit 12 and the display unit 16 changes.

Between the functional unit 12 and the display unit 16 there is furtherprovided a force sensor 20. The force sensor 20 can determine a forceapplied on the touch-sensitive surface 14, for example, from a detectedchange in the distance between the functional unit 12 and the displayunit 16 and a known deformation resistance of the elastic elements 18.However, for the input device 10 it is not necessary that a forceapplication leads to a significant distance change. Alternatively, theforce sensor 20 can also measure a force by means of piezoceramicelements or resistive sensors. Furthermore, the force sensor 20 can alsobe arranged between the functional unit 12 and another component, suchas, for example, a casing (not shown). If the elastic elements 18 wereomitted, the force sensor 20 could also be arranged on a side of thedisplay unit 16 opposite the functional unit 12.

The input device 10 has a vibration sensor 22. The vibration sensor canbe, for example, an acceleration sensor. In the exemplary embodiment,the vibration sensor 22 is arranged on a side of the display unit 16that faces the functional unit 12. The display unit 16 is, in turn,rigidly connected to a casing (not shown), so that an external vibrationacting on the casing is transmitted by the rigid connection via thedisplay unit 16 to the vibration sensor 22. Of course, the vibrationsensor 22 could also be arranged directly on the casing or at anotherlocation (but rigidly with respect to the display unit 16). Thevibration sensor 22 can also be arranged on the functional unit 12 oranother element that is rigidly coupled with the input device 10. Forspace-saving reasons, the vibration sensor 22 can also be arranged in arecess in a component such as the functional unit 12, the display unit16, the force sensor 20 or a casing.

The input device 10 has a control unit 24 which is electrically coupledwith the force sensor 20, the vibration sensor 22 and thetouch-sensitive surface 14. The control unit 24 can be arranged, forexample, on the display unit 16, the functional unit 14 or a casing ofthe input device 10 (not shown). The control unit 24 can also beimplemented by another computing unit such as, for example, a mobiletelephone processor or the control device of a vehicle.

The elastic element 18, the force sensor 20, the vibration sensor 22 andthe control unit 24 are so arranged in such a way relative to thedisplay unit 16 that a view of a display surface of the display unit 16is not impaired by these components.

The control unit 24 is adapted to receive a force signal from the forcesensor 20. The force signal can be an absolute measurement (e.g. innewtons [N]) or can be given in arbitrary units. The force signal canalso include a time indication or permit allocation to a time indicationby the control unit 24.

The control unit 24 is further adapted to receive a touch signal fromthe touch-sensitive surface 14. The touch-signal is indicative ofwhether the touch-sensitive surface 14 is being touched. The touchsignal can further provide information about a size and/or number oftouch surfaces. Thus, for example, a large number of touches over ashort period of time can be interpreted as a further indication ofunintentional touching of the touch-sensitive surface 14 with more thanone finger. A touch threshold value for the touch surface can also beintroduced. The touch threshold value can be dependent on the measuredforce signal and/or vibration signal. The touch signal can also includea time indication or permit allocation to a time indication by thecontrol unit 24.

The control unit 24 is further adapted to receive a vibration signalfrom the vibration sensor 22. The vibration signal is at leastindicative of a vibration in a direction substantially perpendicular tothe touch-sensitive surface 14. Compared with other directions,vibrations in this direction have a higher probability of acceleratingthe functional unit 12 or the user in such a manner that the inputdevice 10 is unintentionally operated and the control unit 24erroneously detects an input. Furthermore, the vibration signal can alsobe indicative of the directions in which the vibrations act. Informationabout a direction of a vibration has the advantage that it is possibleto consider the extent to which a vibration must be taken into accountin the validation of the input. A vibration that is oriented parallel tothe touch-sensitive surface 20 has a lower probability of effectingunintentional operation than a vibration that is orientedperpendicularly to the touch-sensitive surface 20. The vibration signalcan also include a time indication or permit allocation to a timeindication by the control unit 24.

The control unit 24 can receive and process the received signalscontinuously or at periodic time intervals. The control unit 24 can alsobe adapted to initiate the receiving or processing of specific signalswhen a requirement is fulfilled. The sensors can likewise be adapted togenerate or send the signals when a requirement is fulfilled. Thus, forexample, activation and/or reading of the corresponding sensors for theforce signals and/or vibration signals can take place only after a touchhas been registered.

FIG. 2a-2c show sectional views of the first exemplary embodiment underdifferent touch and vibration conditions. FIG. 3 shows, schematically,the associated curves of the detected touch, force and vibration signalsover time, wherein columns a-c in FIG. 3 correspond to the cases fromFIG. 2a-2c . The horizontal lines in the force signal and vibrationsignal diagram in each case indicate a threshold value for detection ofan event that is present (that is to say force application andvibration). The diagram in the fourth line shows in which of the cases adetected force is evaluated as an input after evaluation of the othersignals by the control unit 24.

FIG. 2a shows a sectional view of the first exemplary embodiment duringan operation without external vibration. A user touches thetouch-sensitive surface 14 and exerts a force thereon. Accordingly, atouch signal is measured by the touch-sensitive surface 14 and a forcesignal is measured by the force sensor 20. Since no vibration ispresent, no significant vibration signal above the correspondingthreshold value is measured.

The presence of a touch initiates validation of the force signal by thecontrol unit 24. By correlating the force signal with the other signalsit is hereby determined whether the force application is an intentionalinput. The presence of a touch indicates that the user is at leastoperating the input device 10 and that the force application cannotmerely be the result of a vibration. Since no vibration signal above athreshold value is detected, it is to be expected that the forceapplication is intended by the user. The force application is thusevaluated as an input by the control unit 24, taking into account thetouch signal and the vibration signal. The input signal can betransmitted further for controlling a function, for example.

FIG. 2b shows a sectional view of the first exemplary embodiment withoutoperation and with external vibration 26. In FIG. 3, column b, it willbe seen that the force sensor 20 detects a force. However, thetouch-sensitive surface 14 does not detect a touch. It can be concludedtherefrom that the user is at present not operating the input device 10.It is to be supposed that an erroneous input has been effected by avibration. The validation process can then immediately be terminated bythe control unit 24 and the force signal can be discarded. This has theadvantage that consumption of processor power and energy is reduced.Alternatively, the vibration signal can additionally be taken intoaccount, which actually shows that a vibration 26 is present. Anadvantage of additionally taking account of the vibration signal isimproved validation of the force signal on the basis of two independentsensors.

FIG. 2c shows a sectional view of the first exemplary embodiment duringan operation and with external vibration 26. In FIG. 3, column c, itwill again be seen that the touch-sensitive surface 14 detects a touch.In addition, the force sensor 20 detects a force application. It is notyet apparent from these two pieces of information whether the input isintentional or whether the user is exerting an unintentional forceapplication on the touch-sensitive surface 14 due to the vibration. Ifthe vibration signal is additionally taken into account, it will be seenthat a vibration 26 is present. The force signal is therefore notevaluated by the control unit 24 as an input but is discarded.

FIG. 4 shows schematic diagrams of sensor signals with a time offsetbetween the detected force and the detected vibration. In the diagrams,the two cases b and c are again shown by way of example. Furthermore, inthe case of c, durations of the force application and of the vibrationand a temporal sequence of the detection of the force application and ofthe vibration are taken into account. In case c, a touch, a forceapplication and a vibration are detected. The duration of the forceapplication corresponds substantially to the duration of the vibration.If, on the other hand, the duration of the force application was, forexample, ten times the duration of the vibration, a lesser causalrelationship between the vibration and the force application is to beexpected. However, because durations of substantially equal length aredetected in the present case, it is to be expected that the forceapplication is a result of the vibration.

A time offset is additionally to be observed between the vibration andthe force application, whereby the vibration is detected before theforce application. Information for a possible correlation between thevibration and the force application can be derived both from the timeoffset and from the temporal sequence. The reason for a time offset canbe, for example, damping by the resilient element 18. A vibration whichmoves the display unit 16 is detected by the vibration sensor 22. Themovement of the display unit 16 is initially compensated for by elasticdeformation of the elastic element 18. The vibration is transmitted tothe functional unit 20 with a time offset and therefore detected late atthe force sensor 20. A small time offset suggests a causal relationshipbetween the vibration and the force application. In the case of a largetime offset, on the other hand, it is to be expected that the forceapplication and the vibration have two different causes.

The temporal sequence of the detection can further be evaluated. If avibration is detected temporally before or at the same time as the forceapplication, this suggests a causal relationship between the vibrationand the force application. If, on the other hand, a force application isdetected before the vibration, it is to be expected that the forceapplication is not caused by the vibration.

The temporal causal evaluations discussed above can be carried out bythe control unit 24 for the (optionally additional) validation of anindication of an input. Depending on the evaluation, the input can beevaluated or discarded.

FIG. 5 shows schematic diagrams of sensor signals during an interruptionof a detected force due to a vibration. This is a temporally continuingoperation of the input device 10. If a user wishes to operate a windowlift or to play a music recording, for example, the user must execute aninput for the period of time for which this action is to be carried out.For the input, a force application above a specific threshold must acton the touch-sensitive surface 14 for that period of time and bedetected by the force sensor 20. A vibration can act against thisintentionally long-lasting force application and interrupt it. Thisinterruption is hereafter checked for plausibility by the control unit24.

At least the beginning of the input corresponds to case a according toFIG. 3, that is to say a touch, a force application and no significantvibration are measured. The force application is thus evaluated as aninput. In region d, an interruption of the force application and avibration are then detected. The touch-sensitive surface 14 continues todetect a touch. Since the vibration correlates temporally with theinterruption of the force application, the interruption of the forceapplication is discarded. The operation therefore continues to beevaluated as an input (e.g. of the window lifter or for playing). Assoon as the vibration decreases again, case a is established again. Atouch, a force application and no significant vibration are thusdetected. The force application continues to be detected as an input. Bytaking account of the vibration, an input has been executed over theentire input time even though a vibration led to an unintentionalinterruption of the force application. This resulted in improved, morereliable and thus also more pleasant operation.

FIG. 6 shows a flow diagram of a first exemplary embodiment of a method100 of detecting an input.

In step 102, it is checked whether a touch of the touch-sensitivesurface 16 is detected. As soon as a touch is detected, it is checked instep 104 whether a force application is detected. If no forceapplication is detected, only a touch-specific function 112, such as,for example, a movement of a mouse pointer, is performed. This functionis performed until absence 114 of the touch is detected.

If, on the other hand, a touch and a force application are detected, itis further checked in step 106 whether a vibration is detected. If theabsence of a vibration is detected, the detected force is evaluated asan input in step 110. If, on the other hand, a vibration is detectedwhich correlates, as explained above, with the force application, theinput is discarded and only the touch-specific function 112 isperformed.

Steps 110 and 112 are bordered by a broken line in the flow diagram.This identifies steps which in alternative forms may also comprisefurther or different functions.

FIG. 7 shows a flow diagram of a second exemplary embodiment of a methodof detecting an input. The second exemplary embodiment of the methoddiffers from the first exemplary embodiment (see FIG. 6) substantiallyby step 216.

First of all, in steps 202 to 208—as explained above for thecorresponding steps 102 to 108—a touch, a force application and avibration are detected and a correlation between the vibration and thedetected force is confirmed. In step 216, a component of the detectedforce that is intended by a user is then determined from the detectedvibration and the detected force. The intended force component can bedetermined, for example, by reducing the detected force by avibration-dependent value. The vibration-dependent value can be derivedfrom a scaled vibration signal. Alternatively or in addition, the forcesignal can be newly scaled for the determination. If the intended forcecomponent can be determined, this intended force component is evaluatedas an input.

If the intended force component cannot be determined, the detected forceis discarded as an input. The intended force component can be consideredundeterminable, for example, when a difference between a force signaland the scaled vibration signal is below a threshold value.

Steps 210 and 212 are again shown bordered by a broken line in the flowdiagram. This identifies steps which in alternative forms may alsocomprise further or different functions.

Determining the intended force component has the advantage, inter alia,that erroneous inputs can not only be disregarded but also corrected.Input reliability and input comfort are thereby improved for a user.

FIG. 8 shows a sectional view of a second exemplary embodiment of aninput device 10. The input device 10 according to FIG. 8 differs fromthat of the first exemplary embodiment substantially in that it has aproximity sensor 28 instead of a force sensor 20 (see FIG. 1), and itcan carry out substantially similar validations in respect of theproximity sensor 28 as described above. Of course, an input device 10can have both the force sensor 20 and the proximity sensor 28. However,for the description of a validation of the touch, the force sensor isonly secondary.

The proximity sensor 28 is arranged on the functional unit 12. Theproximity sensor 28 can also be arranged on the display unit 16 or acasing. The proximity sensor 28 can detect, for example, a distancebetween the touch-sensitive surface 14 and an approaching input element(e.g. the finger of a user). A criterion for the detection of anapproach can include, for example, that distance falling below athreshold value.

The validation of a detected touch proceeds analogously to theabove-described validation of a force application. In both validations,an indication of an input is correlated with a vibration and with asecond detected signal. In the case of the validation of a forceapplication, the indication of the input is a detected force and thesecond detected signal is a detected touch. In the case of thevalidation of a touch, on the other hand, the indication of the input isa detected touch and the second detected signal is a detected approach.

Accordingly, if a touch is detected by the touch-sensitive surface 14,it is checked whether an approach and a vibration that correlates withthe touch have been detected. If a vibration or the absence of anapproach is detected, the detected touch is discarded. If, however, anapproach and the absence of a vibration is detected, the touch isevaluated as an input.

FIG. 9 shows a flow diagram of a third exemplary embodiment of a methodof detecting an input 300 on the basis of the input device according toFIG. 8. In step 302, it is checked whether an approach to thetouch-sensitive surface 16 is detected. As soon as an approach isdetected, it is checked in step 304 whether a touch of thetouch-sensitive surface 14 is detected. If no touch is detected, merelyan approach-specific function 312, such as, for example, activation ofdisplay illumination, is performed. This function is performed until theabsence 314 of the approach is detected.

If, on the other hand, an approach and a touch are detected, it isfurther checked in step 306 whether a vibration is detected. If theabsence of a vibration is detected, the detected touch is evaluated asan input in step 310. If, on the other hand, a vibration is detectedwhich correlates with the touch, the input is discarded and only theapproach-specific function 312 is performed.

Steps 310 and 312 are again bordered by a broken line in the flowdiagram. This identifies steps which in alternative forms may alsocomprise further or different functions.

In the examples presented, different features and functions of thepresent disclosure have been described separately from one another andin specific combinations. It will be appreciated, however, that many ofthese features and functions can be freely combined with one another,where this is not explicitly excluded.

1. An input device comprising a touch-sensitive surface; a force sensorwhich is adapted to detect a force applied to the touch-sensitivesurface; a vibration sensor; a control unit which is coupled with theforce sensor, the touch-sensitive surface and the vibration sensor,wherein the control unit is adapted to validate a force detected by theforce sensor as an input in dependence on a touch of the touch-sensitivesurface and in dependence on a vibration detected by the vibrationsensor.
 2. The input device according to claim 1, wherein the controlunit is adapted to evaluate a force detected by the force sensor as aninput in the case where there is a simultaneous touch of thetouch-sensitive surface and where a vibration that correlates temporallywith the force detection is absent.
 3. The input device according toclaim 1, wherein the control unit is adapted to discard a force detectedby the force sensor as an input in the case where there is asimultaneous touch of the touch-sensitive surface and where there is avibration that correlates temporally with the force detection.
 4. Theinput device according to claim 1, wherein the control unit is adaptedto evaluate a temporary interruption of a force detected by the forcesensor as an indication of a termination or interruption of the input inthe absence of a vibration that correlates temporally with theinterruption.
 5. The input device according to claim 1, wherein thecontrol unit is adapted to discard a temporary interruption of a forcedetected by the force sensor as an indication of a termination orinterruption of the input in the case where there is a vibration thatcorrelates temporally with the interruption.
 6. The input deviceaccording to claim 1, wherein the control unit is adapted to determinefrom the detected vibration and the detected force a component of thedetected force that is intended by a user and to evaluate the intendedforce component as an input.
 7. The input device according to claim 1,wherein the control unit is adapted to determine from the detectedvibration and the detected force a component of the detected force thatis intended by a user and to discard the detected force as an input whenthe force component of the detected force that is intended by a user isundeterminable.
 8. The input device according to claim 1, wherein thecontrol unit is adapted to take into account in the validation durationsof the force application and of the vibration and/or a temporal sequenceof the detection of the force application and of the vibration.
 9. Aninput device comprising a touch-sensitive surface; a proximity sensorwhich is adapted to detect an approach of an input element to thetouch-sensitive surface; a vibration sensor; a control unit which iscoupled with the touch-sensitive surface, the proximity sensor and thevibration sensor, wherein the control unit is adapted to validate atouch detected by the touch-sensitive surface as an input in dependenceon an approach detected by the proximity sensor and a vibration detectedby the vibration sensor.
 10. The input device according to claim 9,wherein the control unit is adapted to evaluate a touch detected by thetouch-sensitive surface as an input in the case where an approach issimultaneously detected by the proximity sensor and where a vibrationthat correlates temporally with the touch detection is absent.
 11. Theinput device according to claim 9, wherein the control unit is adaptedto discard a touch detected by the touch-sensitive surface as an inputin the case where an approach is simultaneously detected by theproximity sensor and where there is a vibration that correlatestemporally with the touch detection.
 12. The input device according toclaim 9, wherein the control unit is adapted to evaluate a temporaryinterruption of a touch detected by the touch-sensitive surface as anindication of a termination or interruption of the input in the absenceof a vibration that correlates temporally with the interruption.
 13. Theinput device according to claim 9, wherein the control unit is adaptedto discard a temporary interruption of a touch detected by thetouch-sensitive surface as an indication of a termination orinterruption of the input in the case where there is a vibration thatcorrelates temporally with the interruption.
 14. The input deviceaccording to claim 9, wherein the control unit is adapted to take intoaccount in the validation durations of the touch and of the vibrationand/or a temporal sequence of the detection of the touch and of thevibration.
 15. The input device according to claim 9, further comprisinga display unit.
 16. A motor vehicle comprising an input device accordingto claim
 9. 17. A method of detecting an input at an input device whichhas a touch-sensitive surface, a force sensor for detecting a forceapplied to the touch-sensitive surface and a vibration sensor, whereinthe method comprises: validating a force detected by the force sensor asan input in dependence on a touch of the touch-sensitive surface and independence on a vibration detected by the vibration sensor.
 18. A methodof detecting an input at an input device which has a touch-sensitivesurface, a proximity sensor for detecting an approach of an inputelement to the touch-sensitive surface and a vibration sensor, whereinthe method comprises: validating a touch detected by the touch-sensitivesurface as an input in dependence on an approach detected by theproximity sensor and a vibration detected by the vibration sensor.
 19. Acomputer program product which is stored on a computer-readable medium,wherein the computer program product comprises instructions which, whencarried out on a processor, cause a method according to claim 17 to beperformed.